write-docs

name	write-docs
description	Generate documentation for custom elements based on their manifest data. Use when the user asks to "write docs", "generate documentation", "document this element", "create API docs", or mentions "usage examples" or "component documentation".
tools	Read, Glob, Grep

Write Element Documentation

Generate documentation for custom elements based on their manifest API surface, including usage examples and integration guidance.

Workflow

Phase 1: Gather Element Data

Read the target element's full manifest data:

cem://element/{tagName}

And each sub-resource for complete coverage:

cem://element/{tagName}/attributes
cem://element/{tagName}/slots
cem://element/{tagName}/events
cem://element/{tagName}/css/parts
cem://element/{tagName}/css/custom-properties
cem://element/{tagName}/css/states

Also read project-level guidelines for tone and conventions:

cem://guidelines

Phase 1b: Consult CEM Documentation Guides

Fetch and follow CEM's own guidance on writing effective documentation:

• Documenting Components: https://bennypowers.dev/cem/docs/usage/documenting-components/ Covers JSDoc tags (@summary, @cssprop, @csspart, @slot, @fires), CSS file documentation, and how manifest descriptions are generated from source.

• Writing Demos: https://bennypowers.dev/cem/docs/usage/demos/ Covers demo file structure, <meta> tags for demo metadata, and how cem serve discovers and renders demos from the manifest's demos array.

• Effective MCP Descriptions: https://bennypowers.dev/cem/docs/usage/effective-mcp-descriptions/ Covers writing element and attribute descriptions that work well with AI tools — concise, specific, and machine-readable.

These guides define how documentation feeds into the manifest and tooling. When writing docs, ensure the source-level JSDoc will produce a good manifest, not just a good standalone doc page.

Phase 2: Detect Documentation Conventions

Search the project for existing documentation patterns:

1. Look for existing docs files to match format and structure:

   • Markdown docs in docs/, documentation/, or alongside source
   • Storybook stories (*.stories.ts, *.stories.js)
   • README files in component directories
   • JSDoc/TSDoc in source files, including CSS files

2. Match the project's existing doc style:

   • Heading structure and depth
   • Code example format (HTML-only, with JS, framework-specific)
   • Whether docs include live demos or static examples
   • Tone (formal API reference vs conversational guide)

Phase 3: Generate Documentation

Element Overview

• Purpose statement from the manifest description
• When to use this element (and when not to)
• Quick start example showing the simplest useful usage

Usage Examples

Generate HTML examples using generate_html for:

• Basic usage: Minimal attributes, default slot content
• Common configurations: Each major attribute combination
• Slot variations: Each named slot with appropriate content
• Composition: Element used with related elements from the same library

Attributes Reference

Name	Type	Default	Description

For enum attributes, include a sub-table or list of valid values with descriptions.

Slots Reference

Name	Description	Content Guidelines

Include example HTML showing content in each slot.

Events Reference

Name	Detail	Description

Include JavaScript examples showing how to listen for and handle each event.

Styling

CSS Custom Properties:

Property	Default	Description

CSS Parts:

Part	Description

CSS States:

State	Description

Include a CSS example showing common customizations.

Accessibility

Document any manifest-sourced accessibility patterns:

• ARIA role and keyboard interaction
• Required content for screen readers
• Focus management behavior

Phase 4: Output Format

Adapt the output format to match what the user needs:

• Markdown: Default, suitable for docs sites or READMEs
• HTML: If the project uses HTML documentation
• Storybook: If stories exist, generate a *.stories.ts with knobs for each attribute

Ask the user which format they prefer if it's not clear from context.

Guidelines

• Use manifest data as the source of truth: Don't invent behavior not documented in the manifest
• Generate working examples: Call generate_html to produce valid HTML, don't hand-write examples that might have errors
• Match existing tone: If the project's docs are terse, be terse. If they're tutorial-style, match that
• Link to related elements: When composition makes sense, reference other elements from cem://elements
• Mark uncertainty: If the manifest lacks enough detail for a section, note it rather than guessing
• Docs feed the manifest: When writing JSDoc, remember it generates the manifest. Use @summary for the short description, @cssprop / @csspart / @slot / @fires for API docs. Well-written JSDoc produces a better manifest, which produces better MCP and LSP support.
• Write MCP-effective descriptions: Descriptions should be concise, specific, and machine-readable. Avoid vague language. State what the attribute does, not just what it is. See the CEM guide on effective MCP descriptions.
• Demo files are docs too: Each demo should show one variant or feature. Use <meta itemprop="name"> and <meta itemprop="description"> for demo metadata. Keep demos self-contained with inline imports.
• Escape backticks in template HTML comments: HTML comments inside Lit html tagged template literals are used for slot/part docs. Backticks in these comments (e.g. `currentColor`) break cem's TS transform because they're parsed as template literal boundaries. Escape them with ``` or avoid them.